In a rear wheel drive vehicle, for example, a vehicle driveshaft or propeller shaft transmits torque from the transmission through a differential to the rear wheels of the vehicle, thereby causing the vehicle wheels to be desirably and selectively turned. The propeller shaft also dynamically compensates for the change or modification in the distance between the transmission and the differential that may occur when the vehicle is driven. Hence, the propeller shaft includes a portion or a member, which typically and telescopingly moves along the longitudinal axis of the propeller shaft in response to relative movement between the differential and the transmission, thereby allowing the propeller shaft to dynamically modify its length in response to the movement of the vehicle.
This dynamic length modification is typically achieved by the use of a pair of splined members that are normally manufactured of a relatively heavy material, such as conventional and commercially available iron, and which are respectively and commonly referred to as the “slip yoke” and the “yoke shaft.” Particularly, the yoke shaft is selectively inserted into the slip yoke and is movably coupled to the transmission. The slip yoke is typically coupled to the differential and the respective splines of these members (which are typically broached or “machined” onto the yoke members) intermeshingly cooperate to allow and/or to cause the yoke shaft to rotate the slip yoke in response to the rotation of the transmission, thereby allowing the transmission produced torque to be selectively coupled to the differential by the rotation of the slip yoke. The intermeshed splines also allow the yoke shaft to be movable along the longitudinal axis of the propeller shaft, thereby allowing the propeller shaft to dynamically compensate for changes in the distance between the transmission and the differential and allowing the propeller shaft to desirably operate when the vehicle is driven.
During a frontal crash, energy is imparted upon the vehicle and deforms the components in a longitudinal manner. Typically, the engine and transmission are driven rearward in a frontal crash, causing the propeller shaft to buckle during such an impact. This buckling of the propeller shaft may cause extensive damage to adjacent underbody components, or may even penetrate the passenger compartment. Thus, it would be desirable to provide a propeller shaft with better energy absorption characteristics and one, which provides improved longitudinal deformation during a crash.